Loosening, infection and recurrent dislocation after artificial joint replacement should be considered for total hip revision, and the surgeon should clarify the following questions before revision: Fu Zhihou, Department of Orthopedics, General Hospital of Jinan Military Region n Determine whether it is loosening? n Is it aseptic loosening or infected loosening? n The typing and management of bone defect? n Choice of prosthesis? Is it a partial revision or total rework? n Management of fracture? n Removal of prosthesis and bone cement? I. Loosening of prosthesis: n Symptoms: pain n Signs: pressure points, percussion pain, mobility n X-ray n CT n ECT Imaging of loosening: n 1. Translucent band between cement and bone interface of 2 mm or more; n 2. Progressive widening of translucent band between cement and bone interface; n 3. Displacement of prosthesis; n 4. Translucent band or progressive widening between metal prosthesis and cement interface; n 5. Cement sleeve fracture; n 6. Periosteal hyperplasia; n 7. Prosthetic displacement seen on stress position radiographs or fluoroscopy; n 8. Bone destruction. II. Infectious loosening: n ESR, CRP n Joint puncture leukocyte count n X-ray presentation n Nuclear scan n PET-CT n Intraoperative frozen section III. Classification of bone defects n Acetabular bone defects n Femoral bone defects AAOS classification of acetabular bone defects Type I: for segmental defects. Type IA: peripheral defect, i.e. superior defect, anterior defect, posterior defect; Type IB: central defect (internal wall defect); Type II: cavernous bone defect; Type III: mixed defect; Type IV: pelvic discontinuity defect; Type V: articular fusion defect. Paprosky’s classification n Degree of upward displacement of the hip joint center: ① slight: within 3 cm above the transverse line of the closed foramen; ② obvious: more than 3 cm from the line. n Degree of osteolysis of the sciatic branch: ① slight: osteolysis within 0-7 mm below the transverse line of the foramen magnum; ② moderate: osteolysis within 8-14 mm below the line; ③ severe: osteolysis 15 mm or more below the line. n Degree of internal displacement of the center of the hip joint: ① grade I: lateral to the kohler line; ② grade II: displaced to the kohler line; ③ grade III: medial to the kohler line, extending into the pelvis; n Degree of teardrop osteolysis: ① mild: small amount of bone loss on the lateral margin; ② moderate: complete loss on the lateral margin; ③ severe: bone loss on both the lateral and medial margins. Paprosky’s femoral defects are classified as follows: n Type I: small amount of cancellous bone loss in the proximal femur with intact epiphysis and stem; n Type II: loss of cancellous or structural cortical bone in the proximal femur with incomplete epiphysis and small amount of bone loss in the stem; n Type III: bone loss in the epiphysis and stem; III A: reliable distal fixation at least 4 cm distal to the femoral isthmus; III B: reliable distal fixation can be obtained distal to the femoral isthmus. n Type IV: extensive bone defects of the epiphysis and femoral stem, with thinning of the cortex and widening of the medullary cavity, where reliable distal fixation cannot be obtained. Treatment of bone defects: n Compression implants n Granular implants n Structural implants Bone graft sources: n Autologous implants n Allogeneic implants IV. Bone cement prosthesis: compression implant, titanium mesh, ring, cage V. Prosthetic fractures and treatment: n Type A fractures are avulsion fractures of the large and small rotors (AG and AL types); n Type B fractures are mainly located around the prosthetic stalk or just distal to the tip of the prosthetic stalk; B1 fractures are firmly fixed in the prosthesis; B2 fractures are loose in the prosthesis, but the bone quality is still acceptable; B3 fractures are not only loose in the prosthesis B3 fractures are not only loose, but also have significant bone loss. n Type C fracture is a fracture far from the tip of the prosthesis. Femoral prosthesis and cement removal: n Limited osteotomy: n Greater trochanteric lengthening osteotomy: n Femoral opening: rotor lengthening osteotomy indications (1) n For difficult femoral revision, including stable femoral prosthesis revision due to infection, osteolysis, medial cortical defects; n Biological femoral prosthesis revision: proximal femoral long entry prosthesis, extensive surface long entry prosthesis, long stem or curved stem prosthesis. Indications for rotor lengthening osteotomy (2) n Cemented femoral prosthesis revision: rough surface or collared prosthesis, long-stemmed or curved-stemmed prosthesis, fractured prosthesis, cement located below the isthmus or reinjected cement; n Loose femoral prosthesis but well fixed with cement; n Angulated femoral deformity.